outboard oil injection

[Pat Green]

I still have my 1970 17 with a 2002 120hp nissan.  I have talked to some local guides and they have bypassed the oil injection pump and are mixing oil with gas the old way. Any comments?

[flounderpounder225]

50/50.... some folks just like the knowledge that there is no doubt the engine has enough oil, and go with pre-mix.  The newer motors have pretty reliable oil injection systems, if you do annual maintenance on it, empty the tank, clean the sock or whatever filter device is there, check the oil lines on the powerhead, and watch your oil consumption, I trust the injection systems.  You will use more oil with pre-mix, because injections systems vary the ratio with engine RPM and demand, if you pre-mix, the engine is always getting 50:1 ration, which is not neccessary at idle and slow speed conditions, more smoke etc... Ok, that's my .02.... let the beatings begin...  :pl:
Marc

[wingtime]

Flounder hit the nail on the head.  I personally ditched the oil injection on my Mercury 200.  But it's a mid 90's motor and it is WAY out of warranty.  I don't know anything about the Nissan oil injection system.  The Mercury system has no way of letting you know if the oil is actually flowing...  only a oil pump drive and oil level alarm.  It's a reliable system but I feel better premixing the fuel. One deciding factor was that I didn't have a good place on my boat to mount a remote oil tank. I figure I have to add oil anyways so I just add it to the fuel.   Keep in mind the original oil injection systems were only added for marketing...  the newer ones of course were required for EPA.  Flounder is right about the motors needing less oil at idle and the smoke...  switching to synthetic will help the smoke.  I'm thinking of going to full Amsoil synthetic for next season.  Amsoil recommends a 100:1 mix for motors that require 50:1 so even though it is more expensive you will use less of it.  Personally the 100:1 scares me so I think I will do what my mechanics suggests and mix it 75:1 just to make me feel warm and fuzzy inside.  LOL  Like flounder said it's a matter of personal preference..  If you trust the system and don't want the hassle of premix then keep running it...  Just make sure you maintain the system.  If you don't mid premixing and don't trust it then disable the system and premix the fuel.   How to properly disable a oil injection on a Nissan is another question.

[Capt. Bob]

Just my 2 cents.
I'm a firm believer in a well maintained oil injection system. Why???

1. You're supplying your motor with the properly engineered mix of oil for lubrication. After all, that's why you mix the gas with oil.

2. Under any circumstance, with a properly functioning oil injection, you get the amount of oil necessary. Not too much, not too little. That equates into money well spent.

3. You're treating the environment as if you'll be back at another time because there is no way in hell you can measure the amount of oil and gas mix as accurately as the injector.

4. You can use the oil spec the manufacture recommends. Another cost savings if you really think about it. Unlike a 4 stroker that uses the same supply repeatedly for lubrication and needs to factor in the aging of the lube, 2 strokes get a fresh charge each time. Properly mixed, your engine manufacturer's spec fossil oil will lube just as well as any synthetic. The latest two strokes do use synthetic, at an outrageous cost but their injection systems "sip" it like fine wine thus making it bearable.

If your motor runs well, I can't understand why you would remove the system.

I'm just sayin'

[fitz73222]

Outboard oil injection systems have been very reliable for many years. Early OMC VRO's were really the only systems that had any issues. Most oil pumps are gear driven right off the crankshaft and failures are few and far between. The engine designers and manufacturers test these systems for thousands of hours before releasing them to production. 50-1 oil mix to me is less reliable than oil injection. Most people dont take the time to mix the oil and gas the correct way anyway and cause more harm than good. From a resale perspective, I would much rather purchase an engine with an active oil injection system than a bypassed system because the human error factor now plays a role in engine life expectancy. Don`t always take what the commercial guy`s say about what to do with your engine. Some of the guy`s I have known just basically throw the engines away after 5 years, never touching them until they fall apart or break from neglect.

[seagate]

I would run a injector but my old johnson VRO went bad after I got my boat so I took it off and mix myself but if I had a choice I would rather have a injector OR a 4 stroke.

[MarshMarlowe196]

Just an observation here, BUT-

If you're really concerned about the environment, running oil injection on a typical 2-Stroke outboard engine is only making breathing marginally easier for the fish.  Something like 40% (some estimates bring it up to as much as 70%) of the fuel needed to run at idle is being dumped directly into the water, a little less wide open.  The VRO's had a recirculating feature which would capture this wasted mix and reuse it, but that would only bring it down to about 30% wasted, and besides, VRO's were unreliable, as previously mentioned.

4.  Unlike a 4 stroker that uses the same supply repeatedly for lubrication and needs to factor in the aging of the lube, 2 strokes get a fresh charge each time. Properly mixed, your engine manufacturer's spec fossil oil will lube just as well as any synthetic. The latest two strokes do use synthetic, at an outrageous cost but their injection systems "sip" it like fine wine thus making it bearable.

True, a 4Stroke engine uses a progressively aging supply of oil to lubricate the moving parts, and yes a 2Stroke engine gets a "fresh" shot of oil each stroke, but think about it: this oil is diluted with 50 parts gasoline, give or take.  So even the old oil is really the better lubricant, which is why 4stroke engines will last longer than typical 2stroke engines.  This is purely speaking of older 2stroke engines, as the longevity and lubricity of the modern counterparts is still hotly debated.

Another point, which is moot to this thread because the outboard in question does in fact Vary the amount of oil being delivered throughout the RPM range, - many older oil injected outboards do not vary the amount of oil being injected, instead maintain a steady flow regardless of RPM range.

So- with this engine, bypassing the oil injection system may not serve your wallet.  But, if it makes you feel better, it's really not much different to pre-mix than running the system - plus, you'd get that space back that the oil tank sits in.

[Capt. Bob]

Just an observation here, BUT-
, VRO's were unreliable, as previously mentioned.

VROs, like many things were less reliable when they first came out but that changed rather quickly. I can only speak for OMC types but once the alarm system was put in place and quality filter material used in the oil reservoirs, failures dropped dramatically.

True, a 4Stroke engine uses a progressively aging supply of oil to lubricate the moving parts, and yes a 2Stroke engine gets a "fresh" shot of oil each stroke, but think about it: this oil is diluted with 50 parts gasoline, give or take.  So even the old oil is really the better lubricant, which is why 4stroke engines will last longer than typical 2stroke engines.  This is purely speaking of older 2stroke engines, as the longevity and lubricity of the modern counterparts is still hotly debated.

It's pretty well accepted that an outboard 2 stroke has a lower life expectancy than a 4 stroke but I'm not so sure it's due to lubrication. 2 stroke lube is engineered to be mixed with gas, is at a much lower operating temperature when it enters the crankcase of a 2 stroke and provides lubrication along the entire cylinder wall. I'd bet that the biggest cause of 2 stroke failure is poor maintenance and lack of use in older outboards like mine. Technical advances in machining and metallurgy certainly have helped lazy guys (like myself) extend the life of a motor without doing much more work.    

Another point, which is moot to this thread because the outboard in question does in fact Vary the amount of oil being delivered throughout the RPM range, - many older oil injected outboards do not vary the amount of oil being injected, instead maintain a steady flow regardless of RPM range.

The OMC propaganda that I got with my motors stated that was a big reason for the VRO in that it varied the oil input across the entire operational range.
You don't think they lied to me?

[gran398]

CB, reminds me of an old joke.

The star high school football wide-out comes into the coaches office, he's been causing trouble.

The coach sits him down and says "Son, are you ignorant or apathetic?"

The kid says "Coach, I don't know and I don't care."

Same for OMC back then, as Yammie methodically cleaned their clock.

[MarshMarlowe196]

It's pretty well accepted that an outboard 2 stroke has a lower life expectancy than a 4 stroke but I'm not so sure it's due to lubrication. 2 stroke lube is engineered to be mixed with gas, is at a much lower operating temperature when it enters the crankcase of a 2 stroke and provides lubrication along the entire cylinder wall. I'd bet that the biggest cause of 2 stroke failure is poor maintenance and lack of use in older outboards like mine.

There's many more articles out there to support the idea that 2 stroke engines have a shorter life span due to lack of dedicated lubrication, but here's a good one, in a simple bullet point structure that seems to be popular -

http://www.deepscience.com/articles/engines.html

With further reading, the article also states that 2 strokes cause more pollution by nature, but then again, so do massive oil spills in the gulf, and the fish over here are still biting  

Every oil injected 2stroke outboard I've owned I have bypassed- maybe I'm wrong for doing so, but knowing that the oil is getting burned out, I like the idea of having more than enough oil for the engine at all times, and I only know it has plenty if I pre-mix.

Modern 2 stroke engines (ETEC, HPDI) inject the oil at a different stage of the cycle, which I'm not altogether sure of, and thereby making the lubricant more effective.  I think this is marketing, but it gets technical beyond my understanding, so it might actually work better.  All I know is that I like the idea of my oil not getting burned during combustion.  Makes me feel warm and fuzzy.

Another point, which is moot to this thread because the outboard in question does in fact Vary the amount of oil being delivered throughout the RPM range, - many older oil injected outboards do not vary the amount of oil being injected, instead maintain a steady flow regardless of RPM range.

The OMC propaganda that I got with my motors stated that was a big reason for the VRO in that it varied the oil input across the entire operational range.
You don't think they lied to me?

I never said that the VRO system wasn't variable, merely unreliable (you're right, they dialed it in later).  In fact, VRO stands for Variable Ratio Oiler.

Technical advances in machining and metallurgy certainly have helped lazy guys (like myself) extend the life of a motor without doing much more work.    

Agreed.  Give me warranty or give me death!  

Besides, I think we can all agree that if you're getting more strokes in, then you're lasting longer    

[Capt. Bob]

I read this article earlier.

Speaking of stroking...
Had I been stroking more and lapping less I wouldn't be in the position I'm currently in.

Oh well.

PS... You got mail 8)

[gran398]

Oh my....Is there a moderator present?